1. Field of the Invention
The present invention relates to a dental hand mirror unit having an air stream directed towards the surface of a mirror portion of the unit for cleaning purposes and also to such a hand mirror unit having an illuminating light source.
2. Description of the Prior Art
During use, the reflective surface of a dental hand mirror unit commonly used by dentists quickly becomes obstructed and blurred by, among other things, spray from high-speed drills, dental material and tooth debris, fog and mist. As a result, the quality and workmanship by a dentist can be impaired.
It has therefore been customary for dentists to frequently remove such mirrors from a patient's mouth to clean the reflective surface and then reposition them. This is a tedious, time-consuming and costly process. In addition, interruptions to clean a mirror not only interrupt a dentist's concentration, but also detract from the high degree of accuracy required during a wide variety of dental procedures.
Numerous attempts have been made to solve the problem of foggy, unclean dental mirrors. One typical prior art approach is to direct a stream of air to the surface of a mirror either through a hollow handle of the mirror unit or through an air supply tube clipped to the handle. U.S. Pat. Nos. 1,905,633; 2,809,430; 2,834,109; and 3,082,762 are exemplary of such attempts. However, such devices suffer from many common drawbacks. For example, they lack mechanisms for conveniently controlling the volume of air supplied to the surface of the mirror. That is, many of these devices simply supply a constant volume of air regardless of the needs of the specific dental procedure being performed. Others provide some degree of control of the stream of air through complex and costly mechanisms positioned at a location separated from the hand mirror unit, such as at a console in the dental office. However, such devices are difficult to operate because a dentist must stop work on a patient to adjust the air supplied to the mirror.
Various dental hand mirror units have also been proposed with cumbersome mechanisms on the handle of the unit for controlling the volume of air supplied to the surface of the mirror. As disclosed in U.S. Pat. Nos. 1,925,981, 3,052,031, and 3,164,904, such devices typically include a spring biased push-button operated valve projecting from the handle of the mirror unit. Depressing the button permits a stream of air to flow through the handle of the mirror unit and onto the mirror surface. However, controls of this nature hamper the work of a dentist. For example, the projecting push-buttons may catch on the lip or gum tissue of a patient, and cause much discomfort. In addition, debris and saliva from a patient apparently may bypass the push-buttons and enter the interior of the handle of such mirrors, making such devices extremely difficult to sterilize. Also, mirrors of this type are relatively costly to manufacture and are subject to breakdown as the biasing springs wear.
Still other types of devices have been suggested which control the flow of both water and air, either simultaneously or alternately across the surface of a hand mirror. Examples of such hand mirror units are disclosed in U.S. Pat. Nos. 3,969,924 and 3,986,266. Devices of this type are inherently more complex and costly because both air and water are supplied to the mirror.
In addition, applicant is not aware of any dental hand mirror units which provide an illuminating light source either separate from or together with an air supply for cleaning the surface of the mirror.
Therefore, until the present invention, there has not been a practical, workable, self-cleaning dental hand mirror unit available to dentists, nor such a device capable of illuminating an area within a patient's mouth in which a dentist is working.